Scaling filter for video sharpening

ABSTRACT

A device has a single scaling filter to filter a video signal once to perform both sharpening and scaling. A memory stores original scaling filter coefficients for the scaling filter. An integrated circuit calculates new sharpening-scaling filter coefficients derived from the original scaling filter coefficients and one of sharpening filter coefficients for a sharpening filter and a sharpening strength and applies the new sharpening-scaling filter coefficients to the single scaling filter.

BACKGROUND

1. Field

The present disclosure relates generally to the field of videoprocessing and, more specifically, to techniques for integrating scalingand filtering in a standalone module.

2. Background

The visual appearance of a video signal may be significantly improved byemphasizing the high frequency components of an image. Sharpening issuch a practice to enhance the local contrast at boundaries, and hasbecome one of the most important features in image processing. Amongmany solutions proposed in the past, the “unsharp masking with linearhigh pass filtering” has proven to be a simple and effective method toenhance an image. The video signal may be further sharpened with asharpening filter.

There is therefore a need in the art for techniques for integratingscaling and filtering in a standalone module with a single scalingfilter.

SUMMARY

Techniques for integrating scaling and filtering in a standalone moduleare described herein. In one configuration, a device comprising a singlescaling filter to filter a video signal once to perform both sharpeningand scaling is provided. The device includes a memory to store originalscaling filter coefficients for the scaling filter. The device alsoincludes an integrated circuit to calculate new sharpening-scalingfilter coefficients derived from the original scaling filtercoefficients and one of sharpening filter coefficients for a sharpeningfilter and a sharpening strength and to apply the new sharpening-scalingfilter coefficients to the single scaling filter.

In an aspect, an integrated circuit is provided. The integrated circuitcomprises a single scaling filter to filter a video signal once toperform both sharpening and scaling. The integrated circuit includes amemory to store original scaling filter coefficients for the scalingfilter. The integrated circuit also includes a circuit to calculate newsharpening-scaling filter coefficients derived from the original scalingfilter coefficients and one of sharpening filter coefficients for asharpening filter and a sharpening strength and to apply the newsharpening-scaling filter coefficients to the single scaling filter.

In a still further aspect, a computer program product is provided. Thecomputer program product includes a computer readable medium havinginstructions for causing a computer to filter a video signal x once toperform both sharpening and scaling according to

$z_{q} = {\sum\limits_{{i = -}{\frac{m}{2} + 1}}^{\frac{m}{2}}{d_{i}x_{{\lfloor\frac{q}{s}\rfloor} + i}}}$

where d_(i) are new sharpening-scaling filter coefficients derived fromat least sharpening filter coefficients and original scaling filtercoefficients of a scaling filter; m denotes an even number of taps; sdenotes the scaling ratio; q denotes a coordination index after scaling;and i is an index for a tap of the scaling filter.

In a still further aspect, a processor with a single scaling filter tofilter a video signal once to perform both sharpening and scaling isprovided. The processor includes a memory to store original scalingfilter coefficients for the scaling filter. The processor also includesan integrated circuit to calculate new sharpening-scaling filtercoefficients derived from the original scaling filter coefficients andone of sharpening filter coefficients for a sharpening filter and asharpening strength and applying the new sharpening-scaling filtercoefficients to the single scaling filter.

Additional aspects will become more readily apparent from the detaileddescription, particularly when taken together with the appended drawings

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects and configurations of the disclosure will become more apparentfrom the detailed description set forth below when taken in conjunctionwith the drawings in which like reference characters identifycorresponding elements throughout.

FIG. 1 shows a conventional unsharp masking technology.

FIG. 2 shows a conventional sharpening filter.

FIG. 3 shows a wireless device.

FIG. 4A shows a sharpening filter and a scaling filter.

FIG. 4B shows a standalone module with both sharpening and scaling.

FIG. 5A shows a scaling filter and a sharpening filter.

FIG. 5B shows a standalone module with both scaling and sharpening.

FIG. 6 shows a graph of filter frequency responses for bicubic,sharpening strength=32 and sharpening strength=64.

FIG. 7 shows a modified 4-tap finite impulse response (FIR) filtercircuit for both sharpening and scaling.

FIG. 8 shows an integrated circuit for calculating the values for the4×4 matrix of equation Eq. (17).

FIGS. 9A and 9B show an integrated circuit for calculating equation Eq.(17).

FIG. 10 shows a block diagram for processing a video signal with astandalone sharpening-scaling filter module.

The images in the drawings are simplified for illustrative purposes andare not depicted to scale. To facilitate understanding, identicalreference numerals have been used, where possible, to designateidentical elements that are common to the figures, except that suffixesmay be added, when appropriate, to differentiate such elements.

The appended drawings illustrate exemplary configurations of theinvention and, as such, should not be considered as limiting the scopeof the invention that may admit to other equally effectiveconfigurations. It is contemplated that features or steps of oneconfiguration may be beneficially incorporated in other configurationswithout further recitation.

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any configuration or design described hereinas “exemplary” is not necessarily to be construed as preferred oradvantageous over other configurations or designs.

FIG. 1 shows a conventional unsharp masking technology 10. In FIG. 1,contour enhancement of an output video signal y is achieved by adding,via adder 14, a high-passed (HP) filtered signal from a linear HP filter12 to the original video signal x. The equivalent unsharp maskingsharpening filter coefficients {h_(j), −n≦j≦n} are shown in equation Eq.(1) as

$\begin{matrix}\left\{ \begin{matrix}{h_{0} = {1 + g_{0}}} \\{{h_{j} = g_{j}},{j \neq 0}}\end{matrix} \right. & (1)\end{matrix}$

where {g_(j), −n≦j≦n} denote the coefficients of the linear HP filter12.

FIG. 2 shows a conventional sharpening filter 20. The sharpening outputy is the convolution between the original video signal x and thesharpening filter 20, defined by equation Eq. (2)

$\begin{matrix}{y_{1} = {\sum\limits_{j = {- n}}^{n}{h_{j}{x_{1 + j}.}}}} & (2)\end{matrix}$

The techniques described herein may be used for wireless communications,computing, personal electronics, etc. with a built-in camera module. Anexemplary use of the techniques for wireless communication is describedbelow.

FIG. 3 shows a configuration of a wireless device 100 for use in awireless communication system. The wireless device 100 may be a cellularor camera phone, a terminal, a handset, a personal digital assistant(PDA), or some other device. The wireless communication system may be aCode Division Multiple Access (CDMA) system, a Global System for MobileCommunications (GSM) system, or some other system.

The wireless device 100 is capable of providing bi-directionalcommunications via a receive path and a transmit path. On the receivepath, signals transmitted by base stations are received by an antenna112 and provided to a receiver (RCVR) 114. The receiver 114 conditionsand digitizes the received signal and provides samples to a digitalsection 120 for further processing. On the transmit path, a transmitter(TMTR) 116 receives data to be transmitted from the digital section 120,processes and conditions the data, and generates a modulated signal,which is transmitted via the antenna 112 to the base stations.

The digital section 120 includes various processing, interface andmemory units such as, for example, a modem processor 122, a videoprocessor 124, a controller/processor 126, a display processor (DP) 128,an ARM/DSP 132, a graphics processing unit (GPU) 134, an internal memory136, and an external bus interface (EBI) 138. The modem processor 122performs processing for data transmission and reception (e.g., encoding,modulation, demodulation, and decoding). The video processor 124performs processing on video content (e.g., still images, moving videos,and moving texts) for video applications such as camcorder, videoplayback, and video conferencing. The video processor 124 includes avideo front end (VFE) 125. The VFE may be a MSM 8600 VFE. The videoprocessor 124 performs processing for a camera module 150 having a lens152 to create still images and/or moving videos.

The controller/processor 126 may direct the operation of variousprocessing and interface units within the digital section 120. Thedisplay processor 128 performs processing to facilitate the display ofvideos, graphics, and texts on a display unit 130. The ARM/DSP 132 mayperform various types of processing for the wireless device 100. Thegraphics processing unit 134 performs graphics processing of a graphicspipeline.

The techniques described herein may be used for any of the processors inthe digital section 120, e.g., the video processor 124. The internalmemory 136 stores data and/or instructions for various units within thedigital section 120. The EBI 138 facilitates the transfer of databetween the digital section 120 (e.g., internal memory 136) and a mainmemory 140 along a bus or data line DL.

The digital section 120 may be implemented with one or more DSPs,micro-processors, RISCs, etc. The digital section 120 may also befabricated on one or more application specific integrated circuits(ASICs) or some other type of integrated circuits (ICs).

The techniques described herein may be implemented in various hardwareunits. For example, the techniques may be implemented in ASICs, DSPs,RISCs, ARMs, digital signal processing devices (DSPDs), programmablelogic devices (PLDs), field programmable gate arrays (FPGAs),processors, controllers, micro-controllers, microprocessors, and otherelectronic units.

Combining Sharpening with Scaling

FIG. 4A shows a sharpening filter module 202 and a scaling filter module204. FIG. 4B shows a standalone module 210 with both sharpening andscaling. Sharpening may be implemented as a standalone module in the DP128. However, to relieve the significant amount of the work (such asdesign, implementation and testing) brought by a new module, it may bebetter to combine the sharpening module 202 and the scaling module 204together and use the existing scaling module to do both scaling andsharpening. There are two possible ways for the combination. The firstway is to perform sharpening 202 before the scaling 204, as best seen inFIG. 4A. The second way is shown in FIGS. 5A-5B. In FIG. 5A scaling 302is performed before sharpening 304. FIG. 5B shows a standalone module310 with both scaling and sharpening.

Combine Scaling with a Pre-Sharpening Filter

Returning again to FIGS. 4A and 4B, for the first way (combining scalingwith a pre-sharpening filter), x, y and z denote the signals beforesharpening, after sharpening and after scaling, respectively, and therelationships between y and x as well as z and y are defined inequations Eqs. (3a) and (3b)

$\begin{matrix}{{{y_{1} = {\sum\limits_{j = {- n}}^{n}{h_{j}x_{1 + j}}}};}{and}} & \left( {3a} \right) \\{z_{q} = {\sum\limits_{i = {- 1}}^{2}{c_{i}y_{\lfloor{\frac{q}{s} + i}\rfloor}}}} & \left( {3b} \right)\end{matrix}$

where {c_(i), −1≦i≦2} represent 4-tap finite impulse response (FIR)filter coefficients for scaling; q denotes the coordination index afterscaling; s denotes the scaling ratio; and q/s is the coordination indexbefore scaling. Note that the index of y has been scaled by the scalingratio s since the scaling changes the coordination grid spacing.

Placing equation Eq. (2) into Eq. (3b) modifies the scaling equationinto equation Eq. (4):

$\begin{matrix}{\begin{matrix}{z_{q} = {\sum\limits_{i = {- 1}}^{2}{c_{i}y_{{\lfloor\frac{q}{s}\rfloor} + i}}}} \\{= {\sum\limits_{i = {- 1}}^{2}{\sum\limits_{j = {- n}}^{n}{c_{i}h_{j}x_{{\lfloor\frac{q}{s}\rfloor} + i + j}}}}} \\{= {\sum\limits_{k = {{- 1} - n}}^{n + 2}{f_{k}x_{{\lfloor\frac{q}{s}\rfloor} + k}}}}\end{matrix}{where}{f_{k} = {\sum\limits_{{i \in {\lbrack{{- 1},2}\rbrack}},{j \in {\lbrack{{- n},n}\rbrack}},{{i + j} = k}}{c_{i}{h_{j}.}}}}} & (4)\end{matrix}$

Since a 4-tap FIR filter is used in the DP 128 for scaling, the aboveequation needs to be modified in order to fit into current scalingarchitecture. First, choose n=1, then the Eq. (4) becomes equation Eq.(5)

$\begin{matrix}{z_{q} = {\sum\limits_{k = {- 2}}^{3}{f_{k}{x_{{\lfloor\frac{q}{s}\rfloor} + k}.}}}} & (5)\end{matrix}$

Second, remove the weights for

$x_{{\lfloor\frac{q}{s}\rfloor} - 2}\mspace{14mu} {and}\mspace{14mu} {x_{{\lfloor\frac{q}{s}\rfloor} + 3}.}$

To achieve this, linear predictions are used to predict

${x_{{\lfloor\frac{q}{s}\rfloor} - 2}\mspace{14mu} {and}\mspace{14mu} x_{{\lfloor\frac{q}{s}\rfloor} + 3}},$

defined in equations Eq. (6) and Eq. (7)

$\begin{matrix}{{{x_{{\lfloor\frac{q}{s}\rfloor} + 3} = {\sum\limits_{i = 1}^{4}{a_{i}x_{{\lfloor\frac{q}{s}\rfloor} + 3 - i}}}};}{and}} & (6) \\{x_{{\lfloor\frac{q}{s}\rfloor} - 2} = {\sum\limits_{i = 1}^{4}{b_{i}{x_{{\lfloor\frac{q}{s}\rfloor} - 2 + i}.}}}} & (7)\end{matrix}$

Placing equations Eq. (6) and Eq. (7) into equation Eq. (5), the newsharpening-scaling equation Eq. (8) is formed:

$\begin{matrix}{z_{q} = {\sum\limits_{i = {- 1}}^{2}{d_{i}{x_{{\lfloor\frac{q}{s}\rfloor} + i}.}}}} & (8)\end{matrix}$

Equation Eq. (8) shows that the scaled sharpened output z_(q) isobtained by the convolution between the original (pre-sharpened andpre-scaled) signals

$x_{{\lfloor\frac{q}{s}\rfloor} + i}$

and a 4-tap sharpening-scaling filter d_(i) (−1≦i≦2). The coefficientsof the new sharpening-scaling filter {d_(i), −1≦i≦2} are derived fromthe original scaling filter coefficients {c_(i), −1≦i≦2}, sharpeningfilter coefficients {h_(i), −1≦i≦1}, forward prediction coefficients{a_(i), 1≦i≦4} and backward prediction coefficients {b_(i), 1≦i≦4}, asdescribed in equation Eq. (9)

$\begin{matrix}{\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {{\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}.}} & (9)\end{matrix}$

Note that the new sharpening-scaling equation (i.e. Eq. (8)) has thesame format as the original scaling equation, (i.e. Eq. (3)) but withdifferent coefficients. Therefore, both sharpening and scaling can bedone in one shot with the use of the 32-phase polyphase 4-tap FIRscaling module.

Based on Orthogonality Principle, the optimal forward predictioncoefficients {â_(i), 1≦i≦4} are defined by equation Eq. (10) as

$\begin{matrix}{\begin{bmatrix}{\hat{a}}_{1} \\{\hat{a}}_{2} \\{\hat{a}}_{3} \\{\hat{a}}_{4}\end{bmatrix} = {\begin{bmatrix}r_{0} & r_{1} & r_{2} & r_{3} \\r_{1} & r_{0} & r_{1} & r_{2} \\r_{2} & r_{1} & r_{0} & r_{1} \\r_{3} & r_{2} & r_{1} & r_{0}\end{bmatrix}^{- 1}\begin{bmatrix}r_{1} \\r_{2} \\r_{3} \\r_{4}\end{bmatrix}}} & {(10)\;}\end{matrix}$

where r_(k) is the autocorrelation value, r_(k)=E(x_(n)x_(n-k)). Similarequation is used for the optimal backward predictor coefficients{{circumflex over (b)}_(i), 1≦i≦4}.

To further simplify the calculations for d_(i), choose

$h_{- 1} = {h_{1} = {- \frac{\alpha}{256}}}$

and

${h_{0} + h_{- 1} + h_{1}} = {1.0{\left( {h_{0} = {1 + \frac{2\alpha}{256}}} \right).}}$

Furthermore, a simple first order approximation, instead of thecomplicated optimal solution, is used for forward and backwardpredictions. Then Eq. (9) becomes equation Eq. (11)

$\begin{matrix}{\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{\frac{\alpha}{256} + 1} & \frac{- \alpha}{256} & 0 & 0 \\\frac{- \alpha}{256} & {\frac{2\alpha}{256} + 1} & \frac{- \alpha}{256} & 0 \\0 & \frac{- \alpha}{256} & {\frac{2\alpha}{256} + 1} & \frac{- \alpha}{256} \\0 & 0 & \frac{- \alpha}{256} & {\frac{\alpha}{256} + 1}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}} & (11)\end{matrix}$

where the parameter α is called sharpening strength. One sharpeningstrength yields one set of coefficients {d_(i)}. In this example, a₂, a₃and a₄ are zero; b₂, b₃ and b₄ are set to zero; and b₁ and a₁ are set to1.

Arbitrary scaling in the DP 128 is achieved by the use of a polyphasestructure with 32 phases, and each phase has its own set of FIR filtercoefficients. Let {c_(p,i), −1≦i≦2} represent the original scalingfilter coefficients for phase p, then the new sharpening-scaling filtercoefficients for phase p, denoted as {d_(p,i), −1≦i≦2}, are defined byequation Eq. (12) as

$\begin{matrix}{\begin{bmatrix}d_{p,{- 1}} \\d_{p,0} \\d_{p,1} \\d_{p,2}\end{bmatrix} = {{\begin{bmatrix}{\frac{\alpha}{256} + 1} & \frac{- \alpha}{256} & 0 & 0 \\\frac{- \alpha}{256} & {\frac{2\alpha}{256} + 1} & \frac{- \alpha}{256} & 0 \\0 & \frac{- \alpha}{256} & {\frac{2\alpha}{256} + 1} & \frac{- \alpha}{256} \\0 & 0 & \frac{- \alpha}{256} & {\frac{\alpha}{256} + 1}\end{bmatrix}\begin{bmatrix}c_{p,{- 1}} \\c_{p,0} \\c_{p,1} \\c_{p,2}\end{bmatrix}}.}} & (12)\end{matrix}$

FIG. 6 shows a graph of filter frequency responses for bicubic, asharpening strength=32 and a sharpening strength=64. The originalpolyphase FIR filter coefficients (bicubic scaling) and the new ones(sharpening+bicubic scaling with sharpening strength 32 and 64) arelisted in Tables 1, 2 and 3, below. All of them are in Q9 format whereQ9 format is the actual floating point value and is the value specifiedin the tables downshifted by 9 bits (i.e., divide by 2⁹ or 512).

TABLE 1 Polyphase FIR filter coefficients for bicubic scaling Phasec_(p,−1) c_(p,0) c_(p,1) c_(p,2) 0 0 512 0 0 1 −7 510 8 0 2 −14 507 19 03 −19 501 32 −2 4 −24 493 46 −3 5 −28 483 62 −5 6 −31 472 78 −7 7 −34458 96 −9 8 −36 444 116 −12 9 −37 427 135 −14 10 −37 410 156 −17 11 −37391 177 −19 12 −37 372 199 −22 13 −36 352 221 −25 14 −35 331 243 −27 15−33 309 265 −29 16 −32 288 288 −32 17 −29 265 309 −33 18 −27 243 331 −3519 −25 221 352 −36 20 −22 199 372 −37 21 −19 177 391 −37 22 −17 156 410−37 23 −14 135 427 −37 24 −12 116 444 −36 25 −9 96 458 −34 26 −7 78 472−31 27 −5 62 483 −28 28 −3 46 493 −24 29 −2 32 501 −19 30 0 19 507 −1431 0 8 510 −7

TABLE 2 Polyphase FIR filter coefficients for sharpening + scaling(sharpening strength α = 32) Phase d_(p,−1) d_(p,0) d_(p,1) d_(p,2) 0−64 640 −64 0 1 −72 638 −52 −1 2 −79 633 −38 −3 3 −84 625 −21 −6 4 −89614 −3 −9 5 −92 600 17 −13 6 −94 584 40 −18 7 −95 565 65 −22 8 −96 54591 −28 9 −95 522 118 −33 10 −93 498 146 −38 11 −91 472 175 −44 12 −88445 205 −50 13 −85 417 235 −55 14 −81 388 266 −61 15 −76 358 297 −66 16−72 328 328 −72 17 −66 297 358 −76 18 −61 266 388 −81 19 −55 235 417 −8520 −50 205 445 −88 21 −44 175 472 −91 22 −38 146 498 −93 23 −33 118 522−95 24 −28 91 545 −96 25 −22 65 565 −95 26 −18 40 584 −94 27 −13 17 600−92 28 −9 −3 614 −89 29 −6 −21 625 −84 30 −3 −38 633 −79 31 −1 −52 638−72

TABLE 3 Polyphase FIR filter coefficients for sharpening + scaling(sharpening strength α = 64). Phase d_(p,−1) d_(p,0) d_(p,1) d_(p,2) 0−128 768 −128 0 1 −137 765 −114 −2 2 −144 759 −96 −6 3 −149 748 −76 −104 −154 734 −52 −16 5 −156 717 −26 −22 6 −157 696 2 −28 7 −157 672 33 −368 −156 646 66 −44 9 −153 617 100 −52 10 −149 585 136 −60 11 −145 552 173−69 12 −140 518 211 −78 13 −133 482 250 −86 14 −127 444 289 −95 15 −119406 328 −103 16 −112 368 368 −112 17 −103 328 406 −119 18 −95 289 444−127 19 −86 250 482 −133 20 −78 211 518 −140 21 −69 173 552 −145 22 −60136 585 −149 23 −52 100 617 −153 24 −44 66 646 −156 25 −36 33 672 −15726 −28 2 696 −157 27 −22 −26 717 −156 28 −16 −52 734 −154 29 −10 −76 748−149 30 −6 −96 759 −144 31 −2 −114 765 −137Combine Scaling with a Post-Sharpening Filter

Referring back to FIGS. 5A-5B, in the second way (combining scaling witha post-sharpening filters) x, y and z denote the signals before scaling,after scaling and after sharpening, respectively, and the x-yrelationships and y-z relationship are expressed as in equations Eqs.(13) and (14)

$\begin{matrix}{y_{1} = {\sum\limits_{j = {- 1}}^{2}{c_{j}x_{{\lfloor\frac{1}{s}\rfloor} + j}}}} & (13) \\{z_{q} = {\sum\limits_{i = {- n}}^{n}{h_{j}y_{q + i}}}} & (14)\end{matrix}$

where s represents the scaling ratio. Placing Eq. (13) into Eq. (14)achieves equation Eq. (15)

$\begin{matrix}{{\begin{matrix}{z_{q} = {\sum\limits_{i = {- n}}^{n}{h_{j}y_{q + i}}}} \\{= {\sum\limits_{i = {- n}}^{n}{\sum\limits_{j = {- 1}}^{2}{h_{i}c_{j}x_{{\lfloor\frac{q}{s}\rfloor} + i + j}}}}} \\{= {\sum\limits_{i = {- \frac{n}{s}}}^{\frac{n}{s}}{\sum\limits_{j = {- 1}}^{2}{h_{si}c_{j}x_{{\lfloor\frac{q}{s}\rfloor} + i + j}}}}} \\{= {\sum\limits_{k = {{- \frac{n}{s}} - 1}}^{\frac{n}{s} + 2}{{f_{k}(s)}x_{{\lfloor\frac{q}{s}\rfloor} + k}}}}\end{matrix}{where}{{f_{k}(s)} = {\sum\limits_{{i \in {\lbrack{{- \frac{n}{s}},\frac{n}{s}}\rbrack}},{j \in {\lbrack{{- 1},2}\rbrack}},{{{si} + j} = k}}{h_{si}c_{j}\mspace{14mu} {and}}}}}\mspace{14mu}} & (15)\end{matrix}$

where n is the number of the sharpening filter taps.

Since sharpening is placed after scaling, the coordination grid spacingfor the sharpening input has been changed. This increases theimplementation difficulty. Moreover, since f_(k)(s) is a function of thescaling ratio s, a different scaling ratio yields different set ofcoefficients. Therefore, infinity sets of coefficients are required inorder to support arbitrary scaling, which is essentially prohibitive.

Sharpening Strength Adjustment

Sharpening strength is determined by a user's preference and codingparameters. The user's preference is decided by the user.

Adjusting sharpening strength adaptively according to coding parametersis a mechanism to prevent the unwanted enhancement on annoying codingartifacts. The sharpening strength α is reduced by a certain value if QPis greater than a threshold (since coding artifact is proportional toQP), i.e., shown in equation Eq. (16) as

α=max(α₀ −k(max(0,Qp−τ)),α_(min))  (16)

where α_(min) is the minimum sharpening strength; τ is a thresholddetermined by the distance to the last I frame and codec type; k is atunable constant; Qp is a quantization step size; and α₀ is a defaultsharpening strength. A smaller τ is set for I frames and frames closerto the I frames, while a larger τ is set for frames far away from the Iframes. The threshold τ is also affected by codec type. A larger τ isset for a codec with in-loop deblocker or post deblocker/smoothingfilter, while a smaller τ is set for a codec without deblocker or anyother modules to remove coding artifacts.

HW Changes and HW Interface for New DPs

To implement the sharpening function properly, the following two changesare suggested to be made on FIR filters for new DP designs. First,increase the number of bits for the filter coefficients from s10 to s11(in Q9 format). A signed ten-bit resolution (s10) is sufficient forperforming scaling, but not sufficient enough for performing bothscaling and sharpening. Taking phase 0 as an example, the FIR filtercoefficients are [−2α, 512+4 α, −2α, 0], but an overflow problem occurseven at a sharpening strength α=1. To address this problem, the numberof bits for the filter coefficients needs to be increased.

FIG. 7 shows a modified 4-tap FIR filter circuit 400 for both sharpeningand scaling. A signed eleven-bit resolution (s11) is sufficient forsharpening strength up to 127. It should be noted, that s11 or 11srepresents a signed 11 bits resolution meaning 1 bit to denote a +/−sign and 10 bits for the magnitude. However, unsigned bit resolutionsare denoted for example as u8. In this instance, the 8 represents thenumber of bits for the magnitude with no bits for a sign. Thisnomenclature applies throughout the disclosure and drawings. There arefour input video signals X, each with 8 bits which are multiplied with W(11s bits) at multiplier 402 a. The W represents the sharpening-scalingfilter coefficients. The resultant signal is 19 bits (19s). The outputof the multiplier 402 a is downshifted bitwise by 6 (>>6) at block 404a. In other words, the block 404 a divides the input by 2⁶. Theresultant output signal is 13 bits (13s).

The output of block 404 a is sent to adder 406. The modified 4-tap FIRfilter circuit 400 includes four parallel paths. The first path includesthe multiplier 402 a and downshifter 404 a. The second path includes amultiplier 402 b and downshifter 404 b. The third path includes amultiplier 402 c and downshifter 404 c. The fourth path includes amultiplier 402 d and downshifter 404 d. The first through fourth pathsfunction essentially the same. Thus, adder 406 receives the output fromdownshifters 404 a, 404 b, 404 c and 404 d.

The output of adder 406 is sent to block 408 where downshifting bitwiseby 2 (>>2) takes place. The output of adder 406 is 15 bits (15s). Whenthe output of adder 406 is divided by 2², the resultant output is 13bits (13s). The output of downshifter 408 is sent to adder 410 where a 1bit matrix is added. Thus, the resultant output is now 14 bits (14s).The output of the adder 410 is sent to downshifter block 412 to performa downshift bitwise by 1 or divide by 2¹. The resultant output is now 13bits (13s). The output of the downshifter block 412 is sent to block 414where the output is clamped to values between [0, 255]. The resultantoutput is an eight bit signal (8 u).

Separate sets of coefficients for luminance and chrominance aresuggested. The original scaling design uses the same set of coefficientsfor both luminance and chrominance. It may not be the best choice forsharpening-scaling module since the sharpening enhancement should beapplied only on the luminance component. In the exemplary embodiment,the luminance should use a set of coefficients that are different fromthe ones for the chrominance. For instance, at sharpening strength α=32,the coefficient set listed in the Table 2 is used for luminance, whilethe coefficient set listed in the Table 1 is used for chrominance. Inone configuration, sharpening is not applied on chrominance so theoriginal scaling filter coefficients listed in the Table 1 {C} are usedfor chrominance (i.e., only doing scaling no sharpening). The newsharpening-scaling coefficients listed in the Table 2 {D} are used forluminance (i.e., doing both sharpening and scaling). The value W in FIG.7 is equal to {D} for luminance and {C} for chrominance.

In addition to the above two changes, a new sub-module to calculate thesharpening-scaling filter coefficients is introduced here.

The coefficients {c_(p,k), −1≦k≦2} in Eq. (12) are in Q9 format and thesharpening strength α is in the range of [−127, 127]. Thus, Eq. (12) maybe rewritten as equation Eq. (17)

$\begin{matrix}{\left( {\begin{bmatrix}d_{p,{- 1}} \\d_{p,0} \\d_{p,1} \\d_{p,2}\end{bmatrix} = {{\begin{bmatrix}{\alpha + 256} & {- \alpha} & 0 & 0 \\{- \alpha} & {\alpha + 256} & {- \alpha} & 0 \\0 & {- \alpha} & {{2\alpha} + 256} & {- \alpha} \\0 & 0 & {- \alpha} & {\alpha + 256}\end{bmatrix}\begin{bmatrix}c_{p,{- 1}} \\c_{p,0} \\c_{p,1} \\c_{p,2}\end{bmatrix}} + \begin{bmatrix}128 \\128 \\128 \\128\end{bmatrix}}} \right)\operatorname{>>}8} & (17)\end{matrix}$

where the hardware implementation of above equation is illustrated inFIGS. 8, 9A and 9B.

FIG. 8 shows an integrated circuit 500 for calculating the values forthe 4×4 matrix of equation Eq. (17). The integrated circuit 500 includesan adder 502 which receives the value for the sharpening strength α anda value 256 denoted by [0×100]. This produces a first resultant outputof α+256. The sharpening strength α in input to the adder 502, an adder504 and a negate block 506. Then each of the adder 502, adder 504 andnegate block 506 produce an output. Thus, there are three outputs.

The adder 504 receives as input the sharpening strength α and the outputof adder 502. This produces second resultant output 2α+256. Thesharpening strength at the output of block 506 is −α, the thirdresultant output. In the exemplary embodiment, the first and secondresultant outputs from circuit 500 are 9 bits (9u) while the thirdresultant output is 8 bits (8s).

FIGS. 9A and 9B show an integrated circuit for calculating equation Eq.(17). The integrated circuit is divided into two sub-circuits 600 and700.

The sub-circuit 600 calculates the product of the 4-tap FIR filtercoefficients for scaling denoted as {c_(i), −1≦i≦2} and the 4×4 matrixof equation Eq. (17). There are four paths for inputting the FIR filtercoefficients, C_(p,-1), C_(p,0), C_(p,1) and C_(p,2). The FIR filtercoefficients, C_(p,-1), C_(p,0), C_(p,1) and C_(p,2) are 10 bits (10s).Each path has a multiplier 602, 606, 610 and 614. The multiplier 602receives the input coefficient C_(p,-1) and the first resultant outputof integrated circuit 500, α+256. Likewise, the multiplier 614 receivesthe input coefficient C_(p,2) and the first resultant output ofintegrated circuit 500, α+256.

The multiplier 606 receives the input coefficient C_(p,0) and the secondresultant output of integrated circuit 500, 2α+256. Likewise, themultiplier 610 receives the input coefficient C_(p,1) and the secondresultant output of integrated circuit 500, 2α+256.

Each of the four paths for inputting the FIR filter coefficientsC_(p,-1), C_(p,0), C_(p,1) and C_(p,2) has a parallel branch path. Thus,the parallel branch path for C_(p,-1) has multiplier 604 whichmultiplies C_(p,-1) and the third resultant output of the integratedcircuit 500, −α. The parallel branch path for C_(p,0) has multiplier 608which multiplies C_(p,0) and the third resultant output of theintegrated circuit 500, −α. The parallel branch path for C_(p,1) hasmultiplier 612 which multiplies C_(p,1) and the third resultant outputof the integrated circuit 500, −α. The parallel branch path for C_(p,2)has multiplier 616 which multiplies C_(p2) and the third resultantoutput of the integrated circuit 500, −α.

The first and second resultant outputs of sub-circuit 600 include(α+256)C_(p,-1) and −αC_(p,-1) from multipliers 602 and 604,respectively. The third and fourth resultant outputs of multipliers 606and 608 include (2α+256)C_(p,0) and −αC_(p,0), respectively. The fifthand sixth resultant outputs of multipliers 610 and 612 include(2α+256)C_(p,2) and −αC_(p,2), respectively. The seventh and eighthresultant outputs of multipliers 614 and 616 include (α+256)C_(p,2) and−αC_(p,2). These resultant outputs are inputs to sub-circuit 700 of FIG.9B. The first, third, fifth, and seventh resultant outputs are 19 bits(19s). The second, fourth, sixth and eighth resultant outputs are 17bits (17s).

The sub-circuit 700 calculates the remaining operation of equation Eq.(17) using the inputs from sub-circuit 600. The sub-circuit 700 includesfour adders 702 a, 702 b, 702 c and 702 d. The adder 702 a adds togetherthe first resultant output (α+256)C_(p,-1) and the fourth resultantoutput −αC_(p,0) which produces an output. The output of adder 702 a issent to adder 704 a. The adder 704 a adds the output from adder 702 aand a value of 128. The output of adder 704 a is sent to a downshifter706 a where it is downshifted bitwise by 8 (>>8). For example, thedownshifter 706 a equivalently serves to divide the signal by 2⁸ andproduces d_(p,-1).

The adder 702 b adds together the second resultant output −αC_(p,-1),the third resultant output (2α+256)C_(p,0) and the sixth resultantoutput −αC_(p,1) which produces an output. The output of adder 702 b issent to adder 704 b. The adder 704 b adds the output from adder 702 band a value of 128. The output of adder 704 b is sent to a downshifter706 b where it is downshifted bitwise by 8 (>>8). For example, thedownshifter 706 a equivalently serves to divide the signal by 2⁸ andproduces d_(p,0).

The adder 702 c adds together the fourth resultant output −αC_(p,0), thefifth resultant output (2α+256)C_(p,1) and the eighth resultant output−αC_(p,2) which produces an output. The output of adder 702 c is sent toadder 704 c. The adder 704 c adds the output from adder 702 c and avalue of 128. The output of adder 704 c is sent to a downshifter 706 cwhere it is downshifted bitwise by 8 (>>8) and produces d_(p,1).

The adder 702 d adds together the sixth resultant output −αC_(p,1) andthe seventh resultant output (α+256)C_(p,2) which produces an output.The output of adder 702 d is sent to adder 704 d. The adder 704 d addsthe output from adder 702 d and a value of 128. The output of adder 704d is sent to a downshifter 706 d where it is downshifted bitwise by 8(>>8) and produces d_(p,2).

FIG. 10 shows block diagram 800 for processing a video signal with astandalone sharpening-scaling filter module 808 in a DP 128. The blockdiagram 800 includes a processor circuit 802 which communicates with acoefficient memory 804. The coefficient memory 804 may store the valuesof the FIR filter coefficients C_(p,-1), C_(p,0), C_(p,1) and C_(p,2).The FIR filter coefficients C_(p,-1), C_(p,0), C_(p,1) and C_(p,2) areread from the coefficient memory 804 and sent to the integrated circuitsat block 806. The integrated circuits include circuit 500 andsub-circuits 600 and 700. The output of the integrated circuits at block806 are the new sharpening-scaling filter coefficients for phase p,denoted as {d_(p,i), −1≦i≦2} and are 11 bits. The 11-bit newsharpening-scaling filter coefficients {d_(p,i), −1≦i≦2} are applied tothe sharpening-scaling filter module 808 to generate output Z from theoriginal video signal X.

The block diagram 800 also shows a sharpening strength adjuster 810 toadaptively adjust the sharpening strength α to prevent unwantedenhancement on artifacts. The adaptive adjustment employs equation Eq.(16) above.

As can be appreciated, the equations described herein may be carried outby a processor or a combination of software and hardware. Furthermore,the sharpening strength adjuster 810 is shown in a dotted line box todenote that the sharpening strength adjuster 810 may be outside of theDP 128. For example, the sharpening strength adjuster 810 may be in thevideo processor 124. Likewise, the coefficient memory 804 is shown in adotted line box to denote that the coefficient memory 804 may beexternal to the DP 128.

Only one sharpening parameter is defined in the table below. Note thatmany parameters used in the sharpening-scaling filter module 808, suchas scaling coefficients for a FIR, have already been defined above.Table 4 illustrates a Hardware interface table with the sharpeningstrength α. This can be an input into the integrated circuit 500 of FIG.8.

TABLE 4 Hardware interface Description and Value Programming Name Bitsrange Frequency sharpening_strength S8 Sharpening strength α,Occasionally [−127, 127] (change due to users' preference or QPs)

Sharpening Implementation

Since the hardware (HW) changes cannot be made for some existing DPs,the overflow problem can be overcome with downshifting the FIR filtercoefficients C_(p,-1), C_(p,0), C_(p,1) and C_(p,2) by 1 bit and thencompensating back by gamma correction. Downshifting coefficients by1-bit is equivalent to represent a Q8 value (2⁸) in signed 10 bitresolution. Since the FIR filter coefficients, C_(p,-1), C_(p,0),C_(p,1) and C_(p,2) are divided by two, the new RGB values, aftersharpening and scaling, would be only a half of the values it issupposed to be. These values by the gamma correction (gc) are mappedvalues stored in the column “Original Mapped Value.” Each OriginalMapped Value entry in the Look-up Table (LUT) (Table 5) has a new mappedvalue corresponding to the original mapped value multiplied by two. Anexample of the new LUT is listed in Table 5.

In existing DPs, scaling is performed after CSC, so the pixels processedby the scaling module are in RGB space rather than in YCbCr space. Thismake “separate sets of coefficients for luminance and chrominance” lessattractive.

The calculation for the new sharpening-scaling filter coefficients needto be done in software (SW) since there is no integrated circuit (HW) inthe existing DPs for it.

TABLE 5 New LUT to Compensate for overflow Original New Mapped valuemapped value  0 gc₀ Max(255, 2 * gc₀)  1 gc₁ Max(255, 2 * gc₁)  2 gc₂Max(255, 2 * gc₂) . . . 255 gc₂₅₅ Max(255, 2 * gc₂₅₅)Extend to m-Tap Filter

The finite impulse response (FIR) filter taps of the sharpening-scalingfilter module may be increased. The sharpening-scaling filter moduleshould be ready to adopt changes. Specifically, let m be the number ofthe taps for the FIR filter (suppose m is an even number), then theequations Eq. (2), (3), and (8) are modified accordingly, as equationsEqs. (18), (19) and (20)

$\begin{matrix}{y_{1} = {\sum\limits_{j = {{- \frac{m}{2}} + 1}}^{\frac{m}{2} - 1}{h_{j}x_{1 + j}}}} & (18) \\{z_{q} = {\sum\limits_{i = {{- \frac{m}{2}} + 1}}^{\frac{m}{2}}{c_{i}y_{{\lfloor\frac{q}{s}\rfloor} + i}}}} & (19) \\{z_{q} = {\sum\limits_{i = {{- \frac{m}{2}} + 1}}^{\frac{m}{2}}{d_{i}{x_{{\lfloor\frac{q}{s}\rfloor} + i}.}}}} & (20)\end{matrix}$

The relationship between the new sharpening-scaling filter coefficients

$\left\{ {d_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}}} \right\}$

and the original scaling filter coefficients

$\left\{ {c_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}}} \right\}$

is shown in equation Eq. (21)

$\begin{matrix}{\begin{bmatrix}d_{{- \frac{m}{2}} + 1} \\d_{{- \frac{m}{2}} + 2} \\d_{{- \frac{m}{2}} + 3} \\\cdots \\\cdots \\d_{0} \\d_{1} \\\cdots \\\cdots \\d_{\frac{m}{2}}\end{bmatrix} = {\begin{bmatrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & \cdots & h_{{- \frac{m}{2}} + 1} & 0 & \cdots & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & \cdots & h_{{- \frac{m}{2}} + 2} & h_{{- \frac{m}{2}} + 1} & \cdots & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & \cdots & h_{{- \frac{m}{2}} + 3} & h_{{- \frac{m}{2}} + 2} & \cdots & \cdots & 0 \\\cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots \\\cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & \cdots & h_{0} & h_{- 1} & \cdots & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & \cdots & h_{1} & h_{0} & \cdots & \cdots & h_{{- \frac{m}{2}} + 1} \\\cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots \\\cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots & \cdots \\0 & 0 & 0 & \cdots & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & \cdots & {h_{0} + h_{1}}\end{bmatrix}\begin{bmatrix}c_{{- \frac{m}{2}} + 1} \\c_{{- \frac{m}{2}} + 2} \\c_{{- \frac{m}{2}} + 3} \\\cdots \\\cdots \\c_{0} \\c_{1} \\\cdots \\\cdots \\c_{\frac{m}{2}}\end{bmatrix}}} & (21)\end{matrix}$

In one or more exemplary configurations, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosed configurations is provided toenable any person skilled in the art to make or use the disclosure.Various modifications to these configurations will be readily apparentto those skilled in the art, and the generic principles defined hereinmay be applied to other configurations without departing from the spiritor scope of the disclosure. Thus, the disclosure is not intended to belimited to the configurations shown herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

1. A device comprising: a single scaling filter to filter a video signalonce to perform both sharpening and scaling; a memory to store originalscaling filter coefficients for the scaling filter; and an integratedcircuit to calculate new sharpening-scaling filter coefficients derivedfrom the original scaling filter coefficients and one of sharpeningfilter coefficients for a sharpening filter and a sharpening strengthand to apply the new sharpening-scaling filter coefficients to thesingle scaling filter.
 2. The device of claim 1, wherein the singlescaling filter filters the video signal according to$z_{q} = {\sum\limits_{i = {{- \frac{m}{2}} + 1}}^{\frac{m}{2}}{d_{i}x_{{\lfloor\frac{q}{s}\rfloor} + i}}}$where x is the video signal; d_(i) are the new sharpening-scaling filtercoefficients; m denotes an even number of taps; s denotes the scalingratio; q denotes a coordination index after scaling; and i is an indexfor a tap of the single scaling filter.
 3. The device of claim 2,wherein the single scaling filter comprises a polyphase m-tap finiteimpulse response (FIR) scaling filter.
 4. The device of claim 3, whereinthe new sharpening-scaling filter coefficients are derived according to$\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}$ where d_(i), −1≦i≦2, are the new sharpening-scalingfilter coefficients; c_(i), −1≦i≦2, are the original scaling filtercoefficients; h_(i), −1≦i≦1, are the sharpening filter coefficients;a_(i), 1≦i≦4, are forward prediction coefficients; and b_(i), 1≦i≦4, arebackward prediction coefficients.
 5. The device of claim 4, wherein thepolyphase m-tap finite impulse response (FIR) scaling filter has aplurality of phases.
 6. The device of claim 5, wherein the newsharpening-scaling filter coefficients are calculated according to afirst order approximation of ${\begin{bmatrix}d_{p,{- 1}} \\d_{p,0} \\d_{p,1} \\d_{p,2}\end{bmatrix} = \left( {{\begin{bmatrix}{\alpha + 256} & {- \alpha} & 0 & 0 \\{- \alpha} & {{2\alpha} + 256} & {- \alpha} & 0 \\0 & {- \alpha} & {{2\alpha} + 256} & {- \alpha} \\0 & 0 & {- \alpha} & {\alpha + 256}\end{bmatrix}\begin{bmatrix}c_{p,{- 1}} \\c_{p,0} \\c_{p,1} \\c_{p,2}\end{bmatrix}} + \begin{bmatrix}128 \\128 \\128 \\128\end{bmatrix}} \right)}\operatorname{>>}8$   where$\mspace{20mu} {h_{- 1} = {h_{1} = -}}{\frac{\alpha}{256}*(256)}$  and$\mspace{20mu} {{h_{0} + h_{- 1} + h_{1}} = {1.0\left( {h_{0} = {1 + \frac{2\alpha}{256}}} \right)*256}}$where α is the sharpening strength in a range of −127-+127; a₂, a₃ anda₄ are set to zero; b₂, b₃ and b₄ are set to zero; b₁ and a₁ are set to1; c_(p,i), −1≦i≦2, represent the original scaling filter coefficientsfor a phase p; and d_(p,i), −1≦i≦2, represent the new sharpening-scalingfilter coefficients for the phase p.
 7. The device of claim 6, whereinthe integrated circuit expands the new sharpening-scaling filtercoefficients from 10 bits to 11 bits.
 8. The device of claim 6, furthercomprising: a sharpening strength adjuster to adaptively adjust thesharpening strength to prevent unwanted enhancement on artifacts.
 9. Thedevice of claim 8, wherein the sharpening strength adjuster adaptivelyadjusts the sharpening strength to be reduced by a certain value if Qpis greater than a threshold according toα=max(α₀ −k(max(0,Qp−τ)),α_(min)) where α_(min) is a minimum sharpeningstrength; τ is a threshold determined by a distance to a last I frameand a codec type; k is a tunable constant; Qp is a quantization step;and α₀ is a default sharpening strength.
 10. The device of claim 2,wherein the new sharpening-scaling filter coefficients are calculatedaccording to $\left\lbrack \begin{matrix}d_{- {{\frac{m}{2} + 1}}} \\d_{- {{\frac{m}{2} + 2}}} \\d_{- {{\frac{m}{2} + 3}}} \\\vdots \\d_{0} \\d_{1} \\\vdots \\d_{\frac{m}{2}}\end{matrix} \right\rbrack = \mspace{65mu} {\left\lbrack \begin{matrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & h_{- {{\frac{m}{2} + 1}}} & 0 & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & h_{- {{\frac{m}{2} + 2}}} & h_{- {{\frac{m}{2} + 1}}} & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & h_{- {{\frac{m}{2} + 3}}} & h_{- {{\frac{m}{2} + 2}}} & \cdots & 0 \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & h_{0} & h_{- 1} & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & h_{1} & h_{0} & \cdots & h_{- {{\frac{m}{2} + 1}}} \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\0 & 0 & 0 & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & {h_{0} + h_{1}}\end{matrix} \right\rbrack\left\lbrack \begin{matrix}c_{- {{\frac{m}{2} + 1}}} \\c_{- {{\frac{m}{2} + 2}}} \\c_{- {{\frac{m}{2} + 3}}} \\\vdots \\c_{0} \\c_{1} \\\vdots \\c_{\frac{m}{2}}\end{matrix} \right\rbrack}$ where${d_{i}, -}{{{\frac{m}{2} + 1} \leq i \leq \frac{m}{2}},}$ are the newsharping-scaling filter coefficients; h_(i) are the sharpening filtercoefficients; and${c_{i}, -}{{{\frac{m}{2} + 1} \leq i \leq \frac{m}{2}},}$ donates theoriginal scaling filter coefficients.
 11. The device of claim 1, whereinthe single scaling filter is a portion of a cellular phone, wirelessdevice, wireless communications device, a video game console, a personaldigital assistant (PDA), a laptop computer, or an audio/video-enableddevice.
 12. An integrated circuit comprising: a single scaling filter tofilter a video signal once to perform both sharpening and scaling; amemory to store original scaling filter coefficients for the singlescaling filter; and a circuit to calculate new sharpening-scaling filtercoefficients derived from the original scaling filter coefficients andone of sharpening filter coefficients for a sharpening filter and asharpening strength and to apply the new sharpening-scaling filtercoefficients to the single scaling filter.
 13. The integrated circuit ofclaim 12, wherein the single scaling filter filters the video signalaccording to$z_{q} = {\sum\limits_{{i = -}{\frac{m}{2} + 1}}^{\frac{m}{2}}{d_{i}x_{{\lfloor\frac{q}{s}\rfloor} + i}}}$where x is the video signal; d_(i) are the new sharpening-scaling filtercoefficients; m denotes an even number of taps; s denotes the scalingratio; q denotes a coordination index after scaling; and i is an indexfor a tap of the single scaling filter.
 14. The integrated circuit ofclaim 13, wherein the single scaling filter comprises a polyphase m-tapfinite impulse response (FIR) scaling filter.
 15. The integrated circuitof claim 14, wherein the new sharpening-scaling filter coefficients arederived according to $\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}$ where d_(i), −1≦i≦2, are the new sharpening-scalingfilter coefficients; c_(i), −1≦i≦2, are the original scaling filtercoefficients; h_(i), −1≦i≦1, are the sharpening filter coefficients;a_(i), 1≦i≦4, are forward prediction coefficients; and b_(i), 1≦i≦4, arebackward prediction coefficients.
 16. The integrated circuit of claim15, wherein the polyphase m-tap finite impulse response (FIR) scalingfilter has a plurality of phases.
 17. The integrated circuit of claim16, wherein the new sharpening-scaling filter coefficients arecalculated according to a first order approximation of ${\begin{bmatrix}d_{p,{- 1}} \\d_{p,0} \\d_{p,1} \\d_{p,2}\end{bmatrix} = \left( {{\begin{bmatrix}{\alpha + 256} & {- \alpha} & 0 & 0 \\{- \alpha} & {{2\alpha} + 256} & {- \alpha} & 0 \\0 & {- \alpha} & {{2\alpha} + 256} & {- \alpha} \\0 & 0 & {- \alpha} & {\alpha + 256}\end{bmatrix}\begin{bmatrix}c_{p,{- 1}} \\c_{p,0} \\c_{p,1} \\c_{p,2}\end{bmatrix}} + \begin{bmatrix}128 \\128 \\128 \\128\end{bmatrix}} \right)}\operatorname{>>}8$   where$\mspace{20mu} {h_{- 1} = {h_{1} = -}}{\frac{\alpha}{256}*(256)}$  and$\mspace{20mu} {{h_{0} + h_{- 1} + h_{1}} = {1.0\left( {h_{0} = {1 + \frac{2\alpha}{256}}} \right)*256}}$where α is the sharpening strength in a range of −127-+127; a₂, a₃ anda₄ are set to zero; b₂, b₃ and b₄ are set to zero; b₁ and a₁ are set to1; c_(p,i), −1≦i≦2, represent the original scaling filter coefficientsfor a phase p; and d_(p,i), −1≦i≦2, represent the new sharpening-scalingfilter coefficients for the phase p.
 18. The integrated circuit of claim17, wherein the circuit expands the new sharpening-scaling filtercoefficients from 10 bits to 11 bits.
 19. The integrated circuit ofclaim 17, further comprising: a sharpening strength adjuster toadaptively adjust the sharpening strength to prevent unwantedenhancement on artifacts.
 20. The integrated circuit of claim 19,wherein the sharpening strength adjuster adaptively adjusts thesharpening strength to be reduced by a certain value if Qp is greaterthan a threshold according toα=max(α₀ −k(max(0,Qp−τ)),α_(min)) where α_(min) is a minimum sharpeningstrength; τ is a threshold determined by a distance to a last I frameand a codec type; k is a tunable constant; Qp is a quantization step;and α₀ is a default sharpening strength.
 21. The integrated circuit ofclaim 13, wherein the new sharpening-scaling filter coefficients arecalculated according to $\left\lbrack \begin{matrix}d_{- {{\frac{m}{2} + 1}}} \\d_{- {{\frac{m}{2} + 2}}} \\d_{- {{\frac{m}{2} + 3}}} \\\vdots \\d_{0} \\d_{1} \\\vdots \\d_{\frac{m}{2}}\end{matrix} \right\rbrack = \mspace{65mu} {\left\lbrack \begin{matrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & h_{- {{\frac{m}{2} + 1}}} & 0 & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & h_{- {{\frac{m}{2} + 2}}} & h_{- {{\frac{m}{2} + 1}}} & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & h_{- {{\frac{m}{2} + 3}}} & h_{- {{\frac{m}{2} + 2}}} & \cdots & 0 \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & h_{0} & h_{- 1} & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & h_{1} & h_{0} & \cdots & h_{- {{\frac{m}{2} + 1}}} \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\0 & 0 & 0 & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & {h_{0} + h_{1}}\end{matrix} \right\rbrack\left\lbrack \begin{matrix}c_{- {{\frac{m}{2} + 1}}} \\c_{- {{\frac{m}{2} + 2}}} \\c_{- {{\frac{m}{2} + 3}}} \\\vdots \\c_{0} \\c_{1} \\\vdots \\c_{\frac{m}{2}}\end{matrix} \right\rbrack}$ where${d_{i}, -}{{{\frac{m}{2} + 1} \leq i \leq \frac{m}{2}},}$ are the newsharpening-scaling filter coefficients; h_(i) are the sharpening filtercoefficients; and${c_{i}, -}{{{\frac{m}{2} + 1} \leq i \leq \frac{m}{2}},}$ denoted theoriginal scaling filter coefficients.
 22. The integrated circuit ofclaim 12, wherein the single scaling filter is a portion of a cellularphone, wireless device, wireless communications device, a video gameconsole, a personal digital assistant (PDA), a laptop computer, or anaudio/video-enabled device.
 23. A processor comprising: a single scalingfilter to filter a video signal once to perform both sharpening andscaling; a memory to store original scaling filter coefficients for thescaling filter; and an integrated circuit to calculate newsharpening-scaling filter coefficients derived from the original scalingfilter coefficients and one of sharpening filter coefficients for asharpening filter and a sharpening strength and to apply the newsharpening-scaling filter coefficients to the single scaling filter. 24.The processor of claim 23, wherein the single scaling filter filters thevideo signal according to$z_{q} = {\sum\limits_{{i = -}{\frac{m}{2} + 1}}^{\frac{m}{2}}{d_{i}x_{{\lfloor\frac{q}{s}\rfloor} + i}}}$where x is the video signal; d_(i) are the new sharpening-scaling filtercoefficients; m denotes an even number of taps; s denotes the scalingratio; q denotes a coordination index after scaling; and i is an indexfor a tap of the single scaling filter.
 25. The processor of claim 24,wherein the single scaling filter comprises a polyphase m-tap finiteimpulse response (FIR) scaling filter.
 26. The processor of claim 25,wherein the new sharpening-scaling filter coefficients are derivedaccording to $\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}$ where d_(i), −1≦i≦2, are the new sharpening-scalingfilter coefficients; c_(i), −1≦i≦2, are the original scaling filtercoefficients; h_(i), −1≦i≦1, are the sharpening filter coefficients;a_(i), 1≦i≦4, are forward prediction coefficients; and b_(i), 1≦i≦4, arebackward prediction coefficients.
 27. The processor of claim 26, whereinthe polyphase m-tap finite impulse response (FIR) scaling filter has aplurality of phases.
 28. The processor of claim 27, wherein the newsharpening-scaling filter coefficients are calculated according to afirst order approximation of ${\begin{bmatrix}d_{p,{- 1}} \\d_{p,0} \\d_{p,1} \\d_{p,2}\end{bmatrix} = \left( {{\begin{bmatrix}{\alpha + 256} & {- \alpha} & 0 & 0 \\{- \alpha} & {{2\alpha} + 256} & {- \alpha} & 0 \\0 & {- \alpha} & {{2\alpha} + 256} & {- \alpha} \\0 & 0 & {- \alpha} & {\alpha + 256}\end{bmatrix}\begin{bmatrix}c_{p,{- 1}} \\c_{p,0} \\c_{p,1} \\c_{p,2}\end{bmatrix}} + \begin{bmatrix}128 \\128 \\128 \\128\end{bmatrix}} \right)}\operatorname{>>}8$   where$\mspace{20mu} {h_{- 1} = {h_{1} = -}}{\frac{\alpha}{256}*(256)}$  and$\mspace{20mu} {{h_{0} + h_{- 1} + h_{1}} = {1.0\left( {h_{0} = {1 + \frac{2\alpha}{256}}} \right)*256}}$where α is the sharpening strength in a range of −127-+127; a₂, a₃ anda₄ are set to zero; b₂, b₃ and b₄ are set to zero; b₁ and a₁ are set to1; c_(p,i), −1≦i≦2, represent the original scaling filter coefficientsfor a phase p; and d_(p,i), −1≦i≦2, represent the new sharpening-scalingfilter coefficients for the phase p.
 29. The processor of claim 24,wherein the new sharpening-scaling filter coefficients are calculatedaccording to $\left\lbrack \begin{matrix}d_{- {{\frac{m}{2} + 1}}} \\d_{- {{\frac{m}{2} + 2}}} \\d_{- {{\frac{m}{2} + 3}}} \\\vdots \\d_{0} \\d_{1} \\\vdots \\d_{\frac{m}{2}}\end{matrix} \right\rbrack = \mspace{65mu} {\left\lbrack \begin{matrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & h_{- {{\frac{m}{2} + 1}}} & 0 & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & h_{- {{\frac{m}{2} + 2}}} & h_{- {{\frac{m}{2} + 1}}} & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & h_{- {{\frac{m}{2} + 3}}} & h_{- {{\frac{m}{2} + 2}}} & \cdots & 0 \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & h_{0} & h_{- 1} & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & h_{1} & h_{0} & \cdots & h_{- {{\frac{m}{2} + 1}}} \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\0 & 0 & 0 & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & {h_{0} + h_{1}}\end{matrix} \right\rbrack\left\lbrack \begin{matrix}c_{- {{\frac{m}{2} + 1}}} \\c_{- {{\frac{m}{2} + 2}}} \\c_{- {{\frac{m}{2} + 3}}} \\\vdots \\c_{0} \\c_{1} \\\vdots \\c_{\frac{m}{2}}\end{matrix} \right\rbrack}$ where$d_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$ are the newsharpening-scaling filter coefficients; h_(i) are the sharpening filtercoefficients; and$c_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$ denoted theoriginal scaling filter coefficients.
 30. A wireless device comprising:scaling filtering means for scaling filtering a video signal once toperform both sharpening and scaling; storing means for storing originalscaling filter coefficients for the scaling filtering means; andcalculating means for calculating new sharpening-scaling filtercoefficients derived from the original scaling filter coefficients andone of sharpening filter coefficients for a sharpening filter and asharpening strength and for applying the new sharpening-scaling filtercoefficients to the scaling filtering means.
 31. The device of claim 30,wherein the scaling filtering means comprises a single polyphase m-tapfinite impulse response (FIR) scaling filter.
 32. The device of claim31, wherein the new sharpening-scaling filter coefficients are derivedaccording to $\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}$ where d_(i), −1≦i≦2, are the new sharpening-scalingfilter coefficients; c_(i), −1≦i≦2, are the original scaling filtercoefficients; h_(i), −1≦i≦1, are the sharpening filter coefficients;a_(i), 1≦i≦4, are forward prediction coefficients; and b_(i), 1≦i≦4, arebackward prediction coefficients.
 33. The device of claim 31, whereinthe polyphase m-tap finite impulse response (FIR) scaling filter has aplurality of phases.
 34. The device of claim 33, wherein the newsharpening-scaling filter coefficients are calculated according to afirst order approximation of ${\begin{bmatrix}d_{p,{- 1}} \\d_{p,0} \\d_{p,1} \\d_{p,2}\end{bmatrix} = \left( {{\begin{bmatrix}{\alpha + 256} & {- \alpha} & 0 & 0 \\{- \alpha} & {{2\alpha} + 256} & {- \alpha} & 0 \\0 & {- \alpha} & {{2\alpha} + 256} & {- \alpha} \\0 & 0 & {- \alpha} & {\alpha + 256}\end{bmatrix}\begin{bmatrix}c_{p,{- 1}} \\c_{p,0} \\c_{p,1} \\c_{p,2}\end{bmatrix}} + \begin{bmatrix}128 \\128 \\128 \\128\end{bmatrix}} \right)}\operatorname{>>}8$ where α is the sharpeningstrength in a range of −127-+127; c_(p,i), −1≦i≦2, represent theoriginal scaling filter coefficients for a phase p; and d_(p,i), −1≦i≦2,represent the new sharpening-scaling filter coefficients for the phasep.
 35. The device of claim 30, wherein the new sharpening-scaling filtercoefficients are calculated according to $\begin{matrix}{\begin{bmatrix}d_{{- \frac{m}{2}} + 1} \\d_{{- \frac{m}{2}} + 2} \\d_{{- \frac{m}{2}} + 3} \\\vdots \\d_{0} \\d_{1} \\\vdots \\d_{\frac{m}{2}}\end{bmatrix} = \left\lbrack \begin{matrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & h_{{- \frac{m}{2}} + 1} & 0 & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & h_{{- \frac{m}{2}} + 2} & h_{{- \frac{m}{2}} + 1} & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & h_{{- \frac{m}{2}} + 3} & h_{{- \frac{m}{2}} + 2} & \cdots & 0 \\\vdots & \vdots & \vdots & \cdots & \vdots & \vdots & \cdots & \vdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & h_{0} & h_{- 1} & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & h_{1} & h_{0} & \cdots & h_{{- \frac{m}{2}} + 1} \\\vdots & \vdots & \vdots & \cdots & \vdots & \vdots & \cdots & \vdots \\0 & 0 & 0 & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & {h_{0} + h_{1}}\end{matrix} \right\rbrack} \\{\left\lbrack \begin{matrix}c_{{- \frac{m}{2}} + 1} \\c_{{- \frac{m}{2}} + 2} \\c_{{- \frac{m}{2}} + 3} \\\vdots \\c_{0} \\c_{1} \\\vdots \\c_{\frac{m}{2}}\end{matrix} \right\rbrack}\end{matrix}$ where$d_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$ are the newsharpening-scaling filter coefficients; h_(i) are the sharpening filtercoefficients; $c_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$denotes the original scaling filter coefficients; and m is a number oftaps in the scaling filtering means.
 36. The device of claim 35, whereinthe scaling filtering means is a portion of a cellular phone, wirelessdevice, wireless communications device, a video game console, a personaldigital assistant (PDA), a laptop computer, or an audio/video-enableddevice.
 37. A method comprising: calculating new sharpening-scalingfilter coefficients derived from original scaling filter coefficientsfor a single scaling filter and one of sharpening filter coefficientsfor a sharpening filter and a sharpening strength; applying the newsharpening-scaling filter coefficients to the single scaling filter; andscaling filtering by the single scaling filter a video signal once toperform both sharpening and scaling.
 38. The method of claim 37, whereinthe calculating includes calculating the new sharpening-scaling filtercoefficients according to $\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}$ where d_(i), −1≦i≦2, are the new sharpening-scalingfilter coefficients; c_(i), −1≦i≦2, are the original scaling filtercoefficients; h_(i), −1≦i≦1, are the sharpening filter coefficients;a_(i), 1≦i≦4, are forward prediction coefficients; and b_(i), 1≦i≦4, arebackward prediction coefficients.
 39. The method of claim 37, whereinthe calculating includes calculating the new sharpening-scaling filtercoefficients according to $\begin{matrix}{\begin{bmatrix}d_{{- \frac{m}{2}} + 1} \\d_{{- \frac{m}{2}} + 2} \\d_{{- \frac{m}{2}} + 3} \\\vdots \\d_{0} \\d_{1} \\\vdots \\d_{\frac{m}{2}}\end{bmatrix} = \left\lbrack \begin{matrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & h_{{- \frac{m}{2}} + 1} & 0 & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & h_{{- \frac{m}{2}} + 2} & h_{{- \frac{m}{2}} + 1} & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & h_{{- \frac{m}{2}} + 3} & h_{{- \frac{m}{2}} + 2} & \cdots & 0 \\\vdots & \vdots & \vdots & \cdots & \vdots & \vdots & \cdots & \vdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & h_{0} & h_{- 1} & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & h_{1} & h_{0} & \cdots & h_{{- \frac{m}{2}} + 1} \\\vdots & \vdots & \vdots & \cdots & \vdots & \vdots & \cdots & \vdots \\0 & 0 & 0 & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & {h_{0} + h_{1}}\end{matrix} \right\rbrack} \\{\left\lbrack \begin{matrix}c_{{- \frac{m}{2}} + 1} \\c_{{- \frac{m}{2}} + 2} \\c_{{- \frac{m}{2}} + 3} \\\vdots \\c_{0} \\c_{1} \\\vdots \\c_{\frac{m}{2}}\end{matrix} \right\rbrack}\end{matrix}$ where$d_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$ are the newsharpening-scaling filter coefficients; h_(i) are the sharpening filtercoefficients; $c_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$denotes the original scaling filter coefficients.
 40. A computer programproduct including a computer readable medium having instructions forcausing a computer to: calculate new sharpening-scaling filtercoefficients derived from original scaling filter coefficients for asingle scaling filter and one of sharpening filter coefficients for asharpening filter and a sharpening strength; apply the newsharpening-scaling filter coefficients to the single scaling filter; andscaling filter a video signal once to perform both sharpening andscaling.
 41. The computer program product of claim 40, furthercomprising instructions to cause the computer to calculate the newsharpening-scaling filter coefficients according to $\begin{bmatrix}d_{- 1} \\d_{0} \\d_{1} \\d_{2}\end{bmatrix} = {\begin{bmatrix}{h_{0} + {h_{- 1}b_{1}}} & h_{- 1} & 0 & {h_{1}a_{4}} \\{h_{1} + {h_{- 1}b_{2}}} & h_{0} & h_{- 1} & {h_{1}a_{3}} \\{h_{- 1}b_{3}} & h_{1} & h_{0} & {h_{- 1} + {h_{1}a_{2}}} \\{h_{- 1}b_{4}} & 0 & h_{1} & {h_{0} + {h_{1}a_{1}}}\end{bmatrix}\begin{bmatrix}c_{- 1} \\c_{0} \\c_{1} \\c_{2}\end{bmatrix}}$ where d_(i), −1≦i≦2, are the new sharpening-scalingfilter coefficients; c_(i), −1≦i≦2, are the original scaling filtercoefficients; h_(i), −1≦i≦1, are the sharpening filter coefficients;a_(i), 1≦i≦4, are forward prediction coefficients; and b_(i), 1≦i≦4, arebackward prediction coefficients.
 42. The computer program product ofclaim 40, further comprising instructions to cause the computer tocalculate the new sharpening-scaling filter coefficients according to$\begin{matrix}{\begin{bmatrix}d_{{- \frac{m}{2}} + 1} \\d_{{- \frac{m}{2}} + 2} \\d_{{- \frac{m}{2}} + 3} \\\vdots \\d_{0} \\d_{1} \\\vdots \\d_{\frac{m}{2}}\end{bmatrix} = \left\lbrack \begin{matrix}{h_{0} + h_{- 1}} & h_{- 1} & h_{- 2} & \cdots & h_{{- \frac{m}{2}} + 1} & 0 & \cdots & 0 \\h_{1} & h_{0} & h_{- 1} & \cdots & h_{{- \frac{m}{2}} + 2} & h_{{- \frac{m}{2}} + 1} & \cdots & 0 \\h_{2} & h_{1} & h_{0} & \cdots & h_{{- \frac{m}{2}} + 3} & h_{{- \frac{m}{2}} + 2} & \cdots & 0 \\\vdots & \vdots & \vdots & \cdots & \vdots & \vdots & \cdots & \vdots \\h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & h_{\frac{m}{2} - 3} & \cdots & h_{0} & h_{- 1} & \cdots & 0 \\0 & h_{\frac{m}{2} - 1} & h_{\frac{m}{2} - 2} & \cdots & h_{1} & h_{0} & \cdots & h_{{- \frac{m}{2}} + 1} \\\vdots & \vdots & \vdots & \cdots & \vdots & \vdots & \cdots & \vdots \\0 & 0 & 0 & \cdots & 0 & h_{\frac{m}{2} - 1} & \cdots & {h_{0} + h_{1}}\end{matrix} \right\rbrack} \\{\left\lbrack \begin{matrix}c_{{- \frac{m}{2}} + 1} \\c_{{- \frac{m}{2}} + 2} \\c_{{- \frac{m}{2}} + 3} \\\vdots \\c_{0} \\c_{1} \\\vdots \\c_{\frac{m}{2}}\end{matrix} \right\rbrack}\end{matrix}$ where$d_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$ are the newsharpening-scaling filter coefficients; h_(i) are the sharpening filtercoefficients; $c_{i},{{{- \frac{m}{2}} + 1} \leq i \leq \frac{m}{2}},$denoted the original scaling filter coefficients.